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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/btrfs/xattr.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | fs/btrfs/xattr.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c new file mode 100644 index 000000000..5bb8d8c86 --- /dev/null +++ b/fs/btrfs/xattr.c @@ -0,0 +1,492 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007 Red Hat. All rights reserved. + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/rwsem.h> +#include <linux/xattr.h> +#include <linux/security.h> +#include <linux/posix_acl_xattr.h> +#include <linux/iversion.h> +#include <linux/sched/mm.h> +#include "ctree.h" +#include "btrfs_inode.h" +#include "transaction.h" +#include "xattr.h" +#include "disk-io.h" +#include "props.h" +#include "locking.h" + +int btrfs_getxattr(struct inode *inode, const char *name, + void *buffer, size_t size) +{ + struct btrfs_dir_item *di; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_path *path; + struct extent_buffer *leaf; + int ret = 0; + unsigned long data_ptr; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + /* lookup the xattr by name */ + di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)), + name, strlen(name), 0); + if (!di) { + ret = -ENODATA; + goto out; + } else if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + + leaf = path->nodes[0]; + /* if size is 0, that means we want the size of the attr */ + if (!size) { + ret = btrfs_dir_data_len(leaf, di); + goto out; + } + + /* now get the data out of our dir_item */ + if (btrfs_dir_data_len(leaf, di) > size) { + ret = -ERANGE; + goto out; + } + + /* + * The way things are packed into the leaf is like this + * |struct btrfs_dir_item|name|data| + * where name is the xattr name, so security.foo, and data is the + * content of the xattr. data_ptr points to the location in memory + * where the data starts in the in memory leaf + */ + data_ptr = (unsigned long)((char *)(di + 1) + + btrfs_dir_name_len(leaf, di)); + read_extent_buffer(leaf, buffer, data_ptr, + btrfs_dir_data_len(leaf, di)); + ret = btrfs_dir_data_len(leaf, di); + +out: + btrfs_free_path(path); + return ret; +} + +int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode, + const char *name, const void *value, size_t size, int flags) +{ + struct btrfs_dir_item *di = NULL; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_path *path; + size_t name_len = strlen(name); + int ret = 0; + + ASSERT(trans); + + if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) + return -ENOSPC; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + path->skip_release_on_error = 1; + + if (!value) { + di = btrfs_lookup_xattr(trans, root, path, + btrfs_ino(BTRFS_I(inode)), name, name_len, -1); + if (!di && (flags & XATTR_REPLACE)) + ret = -ENODATA; + else if (IS_ERR(di)) + ret = PTR_ERR(di); + else if (di) + ret = btrfs_delete_one_dir_name(trans, root, path, di); + goto out; + } + + /* + * For a replace we can't just do the insert blindly. + * Do a lookup first (read-only btrfs_search_slot), and return if xattr + * doesn't exist. If it exists, fall down below to the insert/replace + * path - we can't race with a concurrent xattr delete, because the VFS + * locks the inode's i_mutex before calling setxattr or removexattr. + */ + if (flags & XATTR_REPLACE) { + ASSERT(inode_is_locked(inode)); + di = btrfs_lookup_xattr(NULL, root, path, + btrfs_ino(BTRFS_I(inode)), name, name_len, 0); + if (!di) + ret = -ENODATA; + else if (IS_ERR(di)) + ret = PTR_ERR(di); + if (ret) + goto out; + btrfs_release_path(path); + di = NULL; + } + + ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), + name, name_len, value, size); + if (ret == -EOVERFLOW) { + /* + * We have an existing item in a leaf, split_leaf couldn't + * expand it. That item might have or not a dir_item that + * matches our target xattr, so lets check. + */ + ret = 0; + btrfs_assert_tree_write_locked(path->nodes[0]); + di = btrfs_match_dir_item_name(fs_info, path, name, name_len); + if (!di && !(flags & XATTR_REPLACE)) { + ret = -ENOSPC; + goto out; + } + } else if (ret == -EEXIST) { + ret = 0; + di = btrfs_match_dir_item_name(fs_info, path, name, name_len); + ASSERT(di); /* logic error */ + } else if (ret) { + goto out; + } + + if (di && (flags & XATTR_CREATE)) { + ret = -EEXIST; + goto out; + } + + if (di) { + /* + * We're doing a replace, and it must be atomic, that is, at + * any point in time we have either the old or the new xattr + * value in the tree. We don't want readers (getxattr and + * listxattrs) to miss a value, this is specially important + * for ACLs. + */ + const int slot = path->slots[0]; + struct extent_buffer *leaf = path->nodes[0]; + const u16 old_data_len = btrfs_dir_data_len(leaf, di); + const u32 item_size = btrfs_item_size(leaf, slot); + const u32 data_size = sizeof(*di) + name_len + size; + unsigned long data_ptr; + char *ptr; + + if (size > old_data_len) { + if (btrfs_leaf_free_space(leaf) < + (size - old_data_len)) { + ret = -ENOSPC; + goto out; + } + } + + if (old_data_len + name_len + sizeof(*di) == item_size) { + /* No other xattrs packed in the same leaf item. */ + if (size > old_data_len) + btrfs_extend_item(path, size - old_data_len); + else if (size < old_data_len) + btrfs_truncate_item(path, data_size, 1); + } else { + /* There are other xattrs packed in the same item. */ + ret = btrfs_delete_one_dir_name(trans, root, path, di); + if (ret) + goto out; + btrfs_extend_item(path, data_size); + } + + ptr = btrfs_item_ptr(leaf, slot, char); + ptr += btrfs_item_size(leaf, slot) - data_size; + di = (struct btrfs_dir_item *)ptr; + btrfs_set_dir_data_len(leaf, di, size); + data_ptr = ((unsigned long)(di + 1)) + name_len; + write_extent_buffer(leaf, value, data_ptr, size); + btrfs_mark_buffer_dirty(leaf); + } else { + /* + * Insert, and we had space for the xattr, so path->slots[0] is + * where our xattr dir_item is and btrfs_insert_xattr_item() + * filled it. + */ + } +out: + btrfs_free_path(path); + if (!ret) { + set_bit(BTRFS_INODE_COPY_EVERYTHING, + &BTRFS_I(inode)->runtime_flags); + clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags); + } + return ret; +} + +/* + * @value: "" makes the attribute to empty, NULL removes it + */ +int btrfs_setxattr_trans(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + const bool start_trans = (current->journal_info == NULL); + int ret; + + if (start_trans) { + /* + * 1 unit for inserting/updating/deleting the xattr + * 1 unit for the inode item update + */ + trans = btrfs_start_transaction(root, 2); + if (IS_ERR(trans)) + return PTR_ERR(trans); + } else { + /* + * This can happen when smack is enabled and a directory is being + * created. It happens through d_instantiate_new(), which calls + * smack_d_instantiate(), which in turn calls __vfs_setxattr() to + * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the + * inode. We have already reserved space for the xattr and inode + * update at btrfs_mkdir(), so just use the transaction handle. + * We don't join or start a transaction, as that will reset the + * block_rsv of the handle and trigger a warning for the start + * case. + */ + ASSERT(strncmp(name, XATTR_SECURITY_PREFIX, + XATTR_SECURITY_PREFIX_LEN) == 0); + trans = current->journal_info; + } + + ret = btrfs_setxattr(trans, inode, name, value, size, flags); + if (ret) + goto out; + + inode_inc_iversion(inode); + inode->i_ctime = current_time(inode); + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + if (ret) + btrfs_abort_transaction(trans, ret); +out: + if (start_trans) + btrfs_end_transaction(trans); + return ret; +} + +ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) +{ + struct btrfs_key found_key; + struct btrfs_key key; + struct inode *inode = d_inode(dentry); + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_path *path; + int iter_ret = 0; + int ret = 0; + size_t total_size = 0, size_left = size; + + /* + * ok we want all objects associated with this id. + * NOTE: we set key.offset = 0; because we want to start with the + * first xattr that we find and walk forward + */ + key.objectid = btrfs_ino(BTRFS_I(inode)); + key.type = BTRFS_XATTR_ITEM_KEY; + key.offset = 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + path->reada = READA_FORWARD; + + /* search for our xattrs */ + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + struct extent_buffer *leaf; + int slot; + struct btrfs_dir_item *di; + u32 item_size; + u32 cur; + + leaf = path->nodes[0]; + slot = path->slots[0]; + + /* check to make sure this item is what we want */ + if (found_key.objectid != key.objectid) + break; + if (found_key.type > BTRFS_XATTR_ITEM_KEY) + break; + if (found_key.type < BTRFS_XATTR_ITEM_KEY) + continue; + + di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); + item_size = btrfs_item_size(leaf, slot); + cur = 0; + while (cur < item_size) { + u16 name_len = btrfs_dir_name_len(leaf, di); + u16 data_len = btrfs_dir_data_len(leaf, di); + u32 this_len = sizeof(*di) + name_len + data_len; + unsigned long name_ptr = (unsigned long)(di + 1); + + total_size += name_len + 1; + /* + * We are just looking for how big our buffer needs to + * be. + */ + if (!size) + goto next; + + if (!buffer || (name_len + 1) > size_left) { + iter_ret = -ERANGE; + break; + } + + read_extent_buffer(leaf, buffer, name_ptr, name_len); + buffer[name_len] = '\0'; + + size_left -= name_len + 1; + buffer += name_len + 1; +next: + cur += this_len; + di = (struct btrfs_dir_item *)((char *)di + this_len); + } + } + + if (iter_ret < 0) + ret = iter_ret; + else + ret = total_size; + + btrfs_free_path(path); + + return ret; +} + +static int btrfs_xattr_handler_get(const struct xattr_handler *handler, + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + name = xattr_full_name(handler, name); + return btrfs_getxattr(inode, name, buffer, size); +} + +static int btrfs_xattr_handler_set(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, + struct dentry *unused, struct inode *inode, + const char *name, const void *buffer, + size_t size, int flags) +{ + if (btrfs_root_readonly(BTRFS_I(inode)->root)) + return -EROFS; + + name = xattr_full_name(handler, name); + return btrfs_setxattr_trans(inode, name, buffer, size, flags); +} + +static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, + struct dentry *unused, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + int ret; + struct btrfs_trans_handle *trans; + struct btrfs_root *root = BTRFS_I(inode)->root; + + name = xattr_full_name(handler, name); + ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size); + if (ret) + return ret; + + if (btrfs_ignore_prop(BTRFS_I(inode), name)) + return 0; + + trans = btrfs_start_transaction(root, 2); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + ret = btrfs_set_prop(trans, inode, name, value, size, flags); + if (!ret) { + inode_inc_iversion(inode); + inode->i_ctime = current_time(inode); + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + if (ret) + btrfs_abort_transaction(trans, ret); + } + + btrfs_end_transaction(trans); + + return ret; +} + +static const struct xattr_handler btrfs_security_xattr_handler = { + .prefix = XATTR_SECURITY_PREFIX, + .get = btrfs_xattr_handler_get, + .set = btrfs_xattr_handler_set, +}; + +static const struct xattr_handler btrfs_trusted_xattr_handler = { + .prefix = XATTR_TRUSTED_PREFIX, + .get = btrfs_xattr_handler_get, + .set = btrfs_xattr_handler_set, +}; + +static const struct xattr_handler btrfs_user_xattr_handler = { + .prefix = XATTR_USER_PREFIX, + .get = btrfs_xattr_handler_get, + .set = btrfs_xattr_handler_set, +}; + +static const struct xattr_handler btrfs_btrfs_xattr_handler = { + .prefix = XATTR_BTRFS_PREFIX, + .get = btrfs_xattr_handler_get, + .set = btrfs_xattr_handler_set_prop, +}; + +const struct xattr_handler *btrfs_xattr_handlers[] = { + &btrfs_security_xattr_handler, +#ifdef CONFIG_BTRFS_FS_POSIX_ACL + &posix_acl_access_xattr_handler, + &posix_acl_default_xattr_handler, +#endif + &btrfs_trusted_xattr_handler, + &btrfs_user_xattr_handler, + &btrfs_btrfs_xattr_handler, + NULL, +}; + +static int btrfs_initxattrs(struct inode *inode, + const struct xattr *xattr_array, void *fs_private) +{ + struct btrfs_trans_handle *trans = fs_private; + const struct xattr *xattr; + unsigned int nofs_flag; + char *name; + int err = 0; + + /* + * We're holding a transaction handle, so use a NOFS memory allocation + * context to avoid deadlock if reclaim happens. + */ + nofs_flag = memalloc_nofs_save(); + for (xattr = xattr_array; xattr->name != NULL; xattr++) { + name = kmalloc(XATTR_SECURITY_PREFIX_LEN + + strlen(xattr->name) + 1, GFP_KERNEL); + if (!name) { + err = -ENOMEM; + break; + } + strcpy(name, XATTR_SECURITY_PREFIX); + strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); + err = btrfs_setxattr(trans, inode, name, xattr->value, + xattr->value_len, 0); + kfree(name); + if (err < 0) + break; + } + memalloc_nofs_restore(nofs_flag); + return err; +} + +int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, + struct inode *inode, struct inode *dir, + const struct qstr *qstr) +{ + return security_inode_init_security(inode, dir, qstr, + &btrfs_initxattrs, trans); +} |